A. Field of the Invention
The present invention relates to a new and improved coupling that functions as a preloaded member coupling two reciprocating elements. More specifically, the present invention is directed to a new and improved drive rod coupling member for coupling the plunger and piston rod of a gas operated positive displacement pump while maintaining sufficient contact between the two to prevent damage due to separation.
B. Description of the Prior Art
Due to the decreasing supplies of oil and the increasing demand, many different methods of obtaining maximum oil from wells are currently being used. One of these methods employs a gas operated, positive displacement pump that may be operated by high pressure air, natural gas or any other available fluid. These gas operated positive displacement pumps are of rugged construction and are employed for water flooding oil wells.
Often times, several of these pumps are manifolded together to force large quantitites of water in a short amount of time into an oil well in order to increase the oil well's production by making the oil more readily available.
Current pumps employed in the oil field utilize a fluid drive piston connected to a high pressure fluid plunger. Both of these driven components of these pumps are alignment sensitive, since they operate at rapid rates and at high forces. Accordingly, if a slight misalignment between the driven and drive components occurs, excessive plunger and packing wear is caused resulting in rapid deterioration of these elements.
Typically, the piston rod and the plunger of these prior art pumps are rigidly connected requiring precision boring and extreme care in assembly in order to accomplish a high degree of accuracy in axial alignment. A slight misalignment during fabrication or assembly results in rapid deterioration of the plunger, piston rod and the packing for each.
Moreover, any misalignment between the piston rod and the plunger of the pump that is not continuously absorbed by the coupling apparatus, whether it be rigid or otherwise, results in excessive movement of both the piston rod in the drive cylinder packing and the pump plunger in the pump cylinder packing. This excessive movement greatly reduces the life of the packing and if continued over sufficiently long periods of time, can result in piston rod and plunger interference in their respective confinements and eventual destruction thereof.